The present invention relates to an adjustment apparatus for automatically adjusting the position and angle of a deflection yoke installed on a neck part of a cathode ray tube.
A neck part of a cathode ray tube is equipped with a deflection yoke for deflecting an electron beam, a plurality of purity convergence magnets (hereinafter called PC magnets) made of permanent magnets. To display a normal image through a fluorescent surface of the cathode ray tube, PC magnets are installed at appropriate positions with respect to the neck part, and the deflection yoke needs to be positioned at an appropriate position and an appropriate angle with respect to the neck part.
For example, when positioning the deflection yoke with respect to the neck part of the cathode ray tube, a test image is displayed through the fluorescent surface of the cathode ray tube. An operator then evaluates the convergence and purity and determines the rotation of the image with respect to the fluorescent surface, the vertical and horizontal positions thereof, and the distortion thereof, and manually adjust the position and angle of the deflection yoke so that a normal image is displayed properly.
When adjusting the deflection yoke, the deflection yoke is moved in the longitudinal direction along the tube axis of the cathode ray tube, the roll direction with the tube axis, the tilt direction in which the yoke is inclined upwards or downwards about the horizontal axis perpendicular to the tube axis, or the yawing direction in which the yoke is inclined leftwards and rightwards about the vertical axis perpendicular to the tube axis.
Known methods for adjusting the deflection yoke are a method in which a cathode ray tube mounting a deflection yoke on its neck part is loaded into a specialized adjuster device to adjust the yoke, a method in which a cathode ray tube mounted on a palette is conveyed to a predetermined adjustment position by a conveyer to adjust the yoke, and the like.
In any method, however, since an operator manually adjusts the position and angle of the deflection yoke while monitoring an image displayed through a fluorescent screen, the adjustment precision is low and lacks reliability so that satisfactory adjustment results cannot be obtained. Particularly, in conventional methods of manually adjusting the deflection yoke, there is a limitation in responding to images which have come to be finer and finer every year. Also, manual adjustment takes a longer time and burdens more heavily an operator, so that the deflection yoke cannot be securely adjusted in a short time.
The present invention has been made in view of the above situation and has an object of providing an adjustment apparatus capable of automatically adjusting a deflection yoke attached to the neck part of a cathode ray tube to an appropriate position and an appropriate angle with high precision at a high speed.
To achieve the above object, a deflection yoke adjustment apparatus for a cathode ray tube according to the present invention comprises: detection means for detecting an image projected on the cathode ray tube; hold means for holding a deflection yoke attached to a neck part of the cathode ray tube; and adjustment means for moving the deflection yoke held by the hold means, based on a detection result depending on the detection means, thereby to automatically adjust a position and an angle of the deflection yoke with respect to the neck part.
Further, another deflection yoke adjustment apparatus for a cathode ray tube according to the present invention comprises: support means for supporting the cathode ray tube such that a tube axis of the cathode ray tube extends in a horizontal direction; detection means for detecting an image projected on the cathode ray tube supported by the support means; hold means for holding a deflection yoke attached to a neck part of the cathode ray tube supported by the support means; a slide mechanism for moving the deflection yoke held by the hold means, along the tube axis, based on a detection result obtained by the detection means; a rotation mechanism for rotating the deflection yoke held by the hold means, about the tube axis, based on the detection result obtained by the detection means; a tilt mechanism for rotating the deflection yoke held by the hold means, about a horizontal axis perpendicular to the tube axis, based on the detection result obtained by the detection means; and a yawing mechanism for rotating the deflection yoke held by the hold means, about a vertical axis perpendicular to the tube axis, based on the detection result obtained by the detection means.
Also, a deflection yoke adjustment method for a cathode ray tube according to the present invention comprises: a hold step of holding a deflection yoke attached to a neck part of the cathode ray tube arranged at a predetermined adjustment position; a detection step of detecting an image projected through the cathode ray tube; and a adjustment step of moving the deflection yoke held in the hold step, based on a detection result obtained by the detection step, thereby to automatically adjust a position and an angle of the deflection yoke with respect to the neck part.
Further, another deflection yoke adjustment method for a cathode ray tube comprises: a support step of supporting the cathode ray tube at a predetermined adjustment position such that a tube axis of the cathode ray tube extends in a horizontal direction; a hold step of holding a deflection yoke attached to a neck part of the cathode ray tube supported at the predetermined adjustment position in the support step; a detection step of detecting an image projected through the cathode ray tube; a slide step of moving the deflection yoke held in the hold step, along the tube axis, based on a detection result obtained in the detection step; a rotation step of rotating the deflection yoke held in the hold step, about the tube axis, based on the detection result obtained in the detection step; a tilt step of rotating the deflection yoke held in the hold step, about a horizontal axis perpendicular to the tube axis, based on the detection result obtained in the detection step; and a yawing step of rotating the deflection yoke held in the hold step, about a vertical axis perpendicular to the tube axis, based on the detection result obtained in the detection step.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.